Printed circuit board and method of manufacturing the same

ABSTRACT

Disclosed herein is a method of manufacturing a printed circuit board, including the steps of providing a substrate including a first metal layer formed thereon, and forming a patterned first insulation layer on the first metal layer. The method further includes patterning the first metal layer to allow the first metal layer to have a pattern corresponding to that of the first insulation layer, thus forming a first circuit layer, and forming a second insulation layer on the substrate such that the second insulation layer surrounds the first circuit layer and the first insulation layer formed on the first circuit layer. The printed circuit board is advantageous in that process time and process cost can be reduced because a first insulation layer is used as an etching resist and is included as a part of a printed circuit board even after etching.

RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 13/007,550, filed on Jan. 14, 2011, and claims the benefit ofand priority to Korean Patent Application No. KR 10-2010-0031995, filedon Apr. 7, 2010, all of which are incorporated herein by reference intheir entirety into this application.

BACKGROUND

1. Field of the Invention

The present invention relates to a printed circuit board and a method ofmanufacturing the same.

2. Description of the Related Art

Generally, printed circuit boards (PCBs) are manufactured by patterningone or both sides of a substrate, composed of various thermosettingresins, using copper foil, and disposing and fixing ICs or electronicparts on the substrate to form an electric circuit and then coating thesubstrate with an insulator.

Recently, electronic products have been rapidly multi-functionalized andoperated at high speed. In order to keep up with this trend,semiconductor chips, and semiconductor-embedded printed circuit boardsin which semiconductor chips are connected with a main substrate havemade rapid progress, too.

Therefore, printed circuit boards are required to be highly-densifiedand be operated at high speed. In order to meet this requirement,printed circuit boards must be light, thin, short and small, be providedwith microcircuits, have excellent electrical properties, have highreliability and have a high-speed signal transmission structure.

Meanwhile, as printed circuit boards are used in various fields becauseof the progress of electronic products, efforts to simplify a process ofmanufacturing a printed circuit board and reduce the production cost ofa printed circuit board are being made.

FIG. 1 is a flowchart showing a conventional method of manufacturing aprinted circuit board, and FIGS. 2 to 8 are sectional views showing aconventional method of manufacturing a printed circuit board.Hereinafter, the conventional method of manufacturing a printed circuitboard 10 will be described with reference to FIGS. 1 to 8.

First, as shown in FIGS. 1 and 2, a substrate 11 including a first metallayer 12 formed thereon is provided, and then reference holes are formedin the substrate 11 (S10). Then, pretreatment, such as washing,roughening or the like, is conducted.

Subsequently, as shown in FIGS. 1 and 3, a dry film 13 is formed on thepretreated first metal layer 12 (S30).

Subsequently, as shown in FIGS. 1 and 4, the dry film 13 is exposed(S40), and is then developed (S50).

Subsequently, as shown in FIGS. 1 and 5, the first metal layer 12 isetched to form a first circuit layer 14 (S60).

Subsequently, as shown in FIGS. 1 and 6, the dry film 13 is removed(S70). In this case, whether or not the first circuit layer 14 operatesnormally may be checked.

Subsequently, as shown in FIGS. 1 and 7, the exposed first circuit layer14 is black-oxidized. (S80).

Subsequently, as shown in FIGS. 1 and 8, the black-oxidized firstcircuit layer 14 is laminated with an insulation layer 15, and then asecond metal layer 16 for forming an additional circuit layer is formedon the insulation layer 15 (S90).

However, the conventional method of manufacturing the printed circuitboard 10 is problematic in that process time and cost are increasedbecause its processes, such as exposing, developing, removing,laminating and the like, are complicated.

SUMMARY

Accordingly, embodiments of the present invention has been devised tosolve the above-mentioned problems, and the present invention provides amethod of manufacturing a printed circuit board, in which the totalnumber of processes is decreased by omitting the processes oflaminating, exposing, developing and removing, thus reducing processtime and process cost, and a printed circuit board manufactured by themethod.

In accordance with an embodiment of the invention, there is provided aprinted circuit board, including a substrate; a first circuit layerformed on the substrate; a first insulation layer formed on the firstcircuit layer and having a pattern corresponding to that of the firstcircuit layer; and a second insulation layer formed on the substratesuch that the second insulation layer surrounds the first circuit layerand the first insulation layer formed on the first circuit layer.

In accordance with another embodiment, the first insulation layer andthe second insulation layer may be made of materials different from eachother.

In accordance with at least one embodiment, there is provided a methodof manufacturing a printed circuit board, including providing asubstrate including a first metal layer formed thereon; forming apatterned first insulation layer on the first metal layer; patterningthe first metal layer to allow the first metal layer to have a patterncorresponding to that of the first insulation layer, thus forming afirst circuit layer; and forming a second insulation layer on thesubstrate such that the second insulation layer surrounds the firstcircuit layer and the first insulation layer formed on the first circuitlayer.

In accordance with another embodiment, the method may further include,after the providing of the substrate including the first metal layerformed thereon, black-oxidizing the first metal layer.

In accordance with another embodiment, the forming of the patternedfirst insulation layer may include printing the patterned firstinsulation layer on the first metal layer; and curing the firstinsulation layer.

In accordance with another embodiment, the forming of the first circuitlayer, the first circuit layer having a pattern corresponding to that ofthe first insulation layer may be formed by etching the first metallayer using the first insulation layer as an etching resist.

Various objects, advantages and features of the invention will becomeapparent from the following description of embodiments with reference tothe accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

These and other features, aspects, and advantages of the invention arebetter understood with regard to the following Detailed Description,appended Claims, and accompanying Figures. It is to be noted, however,that the Figures illustrate only various embodiments of the inventionand are therefore not to be considered limiting of the invention's scopeas it may include other effective embodiments as well.

FIG. 1 is a flowchart showing a conventional method of manufacturing aprinted circuit board.

FIGS. 2 to 8 are sectional views showing a conventional method ofmanufacturing a printed circuit board.

FIG. 9 is a sectional view showing a printed circuit board, inaccordance with an embodiment of the invention.

FIG. 10 is a flowchart showing a method of manufacturing the printedcircuit board shown in FIG. 9, in accordance with an embodiment of theinvention.

FIGS. 11 to 15 are sectional views showing a method of manufacturing theprinted circuit board shown in FIG. 9, in accordance with an embodimentof the invention.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, which illustrate embodiments ofthe invention. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theillustrated embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art.Like numbers refer to like elements throughout. Prime notation, if used,indicates similar elements in alternative embodiments.

Structure of a Printed Circuit Board

FIG. 9 is a sectional view showing a printed circuit board, inaccordance with an embodiment of the invention. Hereinafter, a printedcircuit board 100 according to this embodiment will be described withreference to FIG. 9. In this embodiment, a single-layered printedcircuit layer is described as the printed circuit board 100, but thepresent invention is not limited thereto. An embodiment of the inventionincludes a multi-layered printed circuit board.

As shown in FIG. 9, the printed circuit board 100 according to thisembodiment includes a substrate 101, a first circuit layer 103, a firstinsulation layer 104, and a second insulation layer 105. Here, the firstcircuit layer 103 and the first insulation layer 104 are configured suchthat they have patterns corresponding to each other.

The substrate 101 is a base of the printed circuit board 100. It isshown in FIG. 9 that the substrate 101 has a single layer structureincluding a metal layer and an insulation layer. However, the presentinvention is not limited thereto, and the substrate 101 may have amulti-layer structure.

The first circuit layer 103 is formed on the substrate 101, and servesto transfer electrical signals.

Here, the first circuit layer 103 may have a predetermined pattern, andmay be made of a conductive metal, such as gold (Au), silver (Ag),copper (Cu), nickel (Ni) or the like.

As further shown in FIG. 9, the first insulation layer 104 is formed onthe first circuit layer 103, and has a pattern corresponding to that ofthe first circuit layer 103.

Here, the first insulation layer 104 is formed only on the first circuitlayer 103, and the second insulation layer is formed on the substrate101 on which the first circuit layer 103 is not formed. The firstinsulation layer 104 may be made of a composite polymer resin which isgenerally used as an interlayer insulation material. For example, thefirst insulation layer 104 may be made of an epoxy resin, such asprepreg, ajinomoto build up film (ABF), FR-4, bismaleimide triazine (BT)or the like.

In accordance with an embodiment, the second insulation layer 105 isformed on the substrate 101.

Here, the second insulation layer 105 may be formed on the firstinsulation layer 104 as well as on the substrate 101 on which the firstcircuit layer 103 is not formed. Further, the second insulation layer105, like the first insulation layer 104, may be made of an epoxy resin,such as prepreg, ajinomoto build up film (ABF), FR-4, bismaleimidetriazine (BT) or the like. Meanwhile, the second insulation layer 105may made of a material different from the material constituting thefirst insulation layer 104, but the material constituting the secondinsulation layer 105 must bond easily with the material constituting thefirst insulation layer 104.

Meanwhile, the printed circuit board 100 may further include a secondmetal layer 106 on the second insulation layer 105, and the second metallayer 106 may be patterned to form a circuit layer.

Method of Manufacturing a Printed Circuit Board

FIG. 10 is a flowchart showing a method of manufacturing the printedcircuit board shown in FIG. 9, in accordance with an embodiment of theinvention, and FIGS. 11 to 15 are sectional views showing a method ofmanufacturing the printed circuit board shown in FIG. 9, in accordancewith an embodiment of the invention. Hereinafter, a method ofmanufacturing a printed circuit board 100 according to this embodimentwill be described with reference to FIGS. 10 to 15.

First, as shown in FIGS. 10 and 11, a substrate 101 including a firstmetal layer 102 formed thereon is provided (S100).

In accordance with an embodiment, an insulation layer including a metallayer formed on at least one side thereof, for example, a copper cladlaminate (CCL) may be used as the substrate 101. Further, the substrate101 may be provided with reference holes for fitting it with otherconstituents.

Meanwhile, the first metal layer 102 is converted into a first circuitlayer 103 later, and may be made of a conductive metal.

Subsequently, as shown in FIGS. 10 and 12, the surface of the firstmetal layer 102 is black-oxidized (S200).

Here, the black-oxidizing process is a process for roughening thesurface of the first metal layer 102 in order to improve the adhesionbetween the first metal layer 102 and a first insulation layer 104 or asecond insulation layer 105 and increase the heat resistance of thefirst metal layer 102. For example, when the first metal layer 102 ismade of copper (Cu), the black-oxidizing process may be conducted byprecipitating Cu₂O (brown) or CuO (black) on the surface of the firstmetal layer 102.

Subsequently, as shown in FIGS. 10 and 13, a first insulation layer 104is formed on the first metal layer 102 (S300, S400).

In this case, the first insulation layer 104 may be formed on the firstmetal layer 102 by a printing method (S300). Concretely, the firstinsulation layer 104 may be formed on the first metal layer 102 byproviding a screen for printing, applying the first insulation layer onthe screen and then pressing the first metal layer 102 using a squeegee.In this case, the first insulation layer 104 has a pattern correspondingto the pattern to be formed on the first metal layer 102.

Then, the first insulation layer 104 formed on the first metal layer 102may be cured (S400). In this case, the first insulation layer 104 may becured by applying heat and pressure thereto.

Subsequently, as shown in FIGS. 10 and 14, the first metal layer 102 ispatterned to form a first circuit layer 103 (S500).

The patterning of the first circuit layer 103 may be conducted byetching, and, in this case, the first insulation layer 104 serves as anetching resist. That is, when an etchant is applied on the first metallayer 102 formed thereon with the first insulation layer 103, only theportion on which the first insulation layer 104 is not formed is etched,whereas the portion on which the first insulation layer is formed is notetched, thus forming the first circuit layer 103 having a patterncorresponding to the pattern of the first insulation layer 104.Therefore, it is preferred that the first insulation layer 104 be madeof a material which cannot be removed by the etchant for etching thefirst metal layer 102. However, the first insulation layer 104, unlike ageneral etching resist, is not removed even after the etching process iscompleted, and is included as a part of the printed circuit board 100.

Meanwhile, after the first circuit layer 103 is formed, whether or notthe first circuit layer 103 operates normally may be checked.

Subsequently, as shown in FIGS. 10 and 15, a second insulation layer 105is formed on the substrate 101 such that the second insulation layersurrounds the first circuit layer and the first insulation layer formedon the first circuit layer (S600).

In this case, it is shown in FIG. 15 that the top surface of the secondinsulation layer 105 is flush with the top surface of the firstinsulation layer 104. However, the second insulation layer 105 shown inFIG. 15 is an illustrative example, and the second insulation layer 105may be formed on the first insulation layer 104 as well as on thesubstrate 101 on which the first circuit layer 103 and the firstinsulation layer are not formed. Further, the second insulation layer105 may be made of a material which bonds easily with the firstinsulation layer 104.

Meanwhile, the printed circuit board 100 may further include a secondmetal layer 106 on the second insulation layer 105, and the second metallayer 106 may be patterned to form a circuit layer.

Through the above processes, the printed circuit board 100 shown in FIG.15 according to an embodiment of the present invention is manufactured.

As described above, according to the present invention, process time andprocess cost can be reduced because a first insulation layer is used asan etching resist and is included as a part of a printed circuit boardeven after etching.

Further, according to the present invention, two processes including apre-treating process before laminating a dry film and a black-oxidizingprocess before laminating an insulation layer are unified into ablack-oxidizing process before forming a first insulation layer, thusreducing the manufacturing time and cost of a printed circuit board.

Embodiments of the present invention may suitably comprise, consist orconsist essentially of the elements disclosed and may be practiced inthe absence of an element not disclosed. For example, it can berecognized by those skilled in the art that certain steps can becombined into a single step.

The terms and words used in the present specification and claims shouldnot be interpreted as being limited to typical meanings or dictionarydefinitions, but should be interpreted as having meanings and conceptsrelevant to the technical scope of the present invention based on therule according to which an inventor can appropriately define the conceptof the term to describe the best method he or she knows for carrying outthe invention.

The singular forms “a,” “an,” and “the” include plural referents, unlessthe context clearly dictates otherwise.

As used herein and in the appended claims, the words “comprise,” “has,”and “include” and all grammatical variations thereof are each intendedto have an open, non-limiting meaning that does not exclude additionalelements or steps.

Ranges may be expressed herein as from about one particular value,and/or to about another particular value. When such a range isexpressed, it is to be understood that another embodiment is from theone particular value and/or to the other particular value, along withall combinations within said range.

Although the present invention has been described in detail, it shouldbe understood that various changes, substitutions, and alterations canbe made hereupon without departing from the principle and scope of theinvention. Accordingly, the scope of the present invention should bedetermined by the following claims and their appropriate legalequivalents.

What is claimed is:
 1. A method of manufacturing a printed circuitboard, comprising: providing a substrate including a first metal layerformed thereon; forming a patterned first insulation layer on the firstmetal layer; patterning the first metal layer to allow the first metallayer to have a pattern corresponding to that of the first insulationlayer, thus forming a first circuit layer; and forming a secondinsulation layer on the substrate such that the second insulation layersurrounds the first circuit layer and the first insulation layer formedon the first circuit layer.
 2. The method according to claim 1, furthercomprising: after the providing of the substrate including the firstmetal layer formed thereon, black oxidizing the first metal layer. 3.The method according to claim 1, wherein the forming of the patternedfirst insulation layer comprises: printing the patterned firstinsulation layer on the first metal layer; and curing the firstinsulation layer.
 4. The method according to claim 1, wherein, in theforming of the first circuit layer, the first circuit layer having apattern corresponding to that of the first insulation layer is formed byetching the first metal layer using the first insulation layer as anetching resist.